The present invention relates to a network of nodes and links designed and/or optimized using a genetic process, and particularly, although not exclusively to a communications network.
There are numerous examples of utility service networks which comprise a plurality of nodes interconnected by a plurality of links. Services are transferred between node equipment at the nodes along link equipment. Examples of such networks include electricity supply networks, in which the links comprise high voltage power cables and the nodes comprise power stations, generators, substations and the like; water supply networks in which the node equipment comprises reservoirs, valves, water towers, and customer sites, and the links comprise supply pipelines; gas supply networks where the node equipment comprises sea platforms, storage tanks, customer sites, distribution centres and valves, and the links comprise gas pipelines; Intercity road networks in which the nodes comprise towns or cities and the links comprise roads, and similarly railway networks and airline networks, and more particularly communications networks such as a computer network in which the nodes may comprise computer equipment and the links may comprise communication links, or telephony service communications networks, in which the nodes may comprise exchange equipment, and the links may comprise terrestrial, undersea, airborne or satellite communications channels,
Taking the example of the telephone service network, a conventional telecommunications network comprises a plurality of exchanges for connecting and directing communications channels between customer sites, and a plurality of communications links connecting the exchanges and the customer sites. A customer site may comprise a single piece of equipment, for example a single telephone handset, or may comprise a switchboard facility at a customer""s premises, enabling incoming calls to be directed to a plurality of individual telephone handsets.
Where it is required to connect a new customer site to an existing communications network, or where it is required to set up a communications network in a locality from scratch (a xe2x80x9cgreen fieldxe2x80x9d network) the design of the new network, or the design of the modification to the network, is conventionally carried out by a human designer or a team of designers. Network design is a skilled activity that relies on human expertise. There are sections of networks which can be automatically designed, once the necessary design parameters or specifications for the network have been established. Particular sections of a network may be designed by existing algorithms and design techniques implemented by computer. Nevertheless, in general, human network designers tend to use such algorithms and techniques as tools in designing a network, and unless the human network designers can be convinced that the tools produce an optimum solution to the problem of network design, the human designers will generally rely upon their own experience and intuition in designing a network, rather than relying upon the algorithms to produce a design for a complete network.
The number and variety of parameters that the human network designer must take account of in designing a network is large. Some of the parameters familiar to human designers of telecommunications networks include selecting the type of switching network, for example packet switched network or circuit switched network (PSN or CSN), layout of network topology, availability, growth, survivability, reliability, delay, performance, cost, call blocking, grade of service, quality of service, hops, capacity, band width, and fixed alternative or dynamic alternative routing. Further, synchronous and asynchronous networks require different approaches to design optimization.
According to a first aspect of the present invention, there, is provided a method of processing data signals representing a plurality of networks, each network comprising a plurality of node equipment at nodes of the network, and connecting the node equipment a plurality of link, each comprising link equipment, said method comprising steps of generating a population of individual hierarchical signals, each describing a respective network; testing each hierarchical signal to check that it represents a viable network; testing each hierarchical signal which represents a viable network against one or more predetermined test parameters; selecting a set of said hierarchical signals depending upon a result of said step (c); evolving said set of selected hierarchical signals to produce a next generation population of hierarchical signals.